Pressure actuated circuit interrupter resettable by fluid
pressure also having pressure actuated detent means



P 26, 1957 w R. THOMAS ETAL 3,344,249

PRESSURE ACTUATED CI RCUIT INTERRUPTER RESET'I'ABLE BY FLUID PRESSURE ALSO HAVING PRESSURE ACTUATED DETENI MEANS Filed June 9, 1966 2 Sheets-Sheet 2 Mil/44 z 7/01/45 65%63! 249M626 I NVE N TOR- United States Patent G land Filed June 9, 1966, Ser. No. 556,395 13 Claims. (Cl. 200-82) This invention relates to an improved electrical switching device or interrupter adapted to be used in an electrical connector body typically having a plurality of ter minal members forming a plurality of circuits.

US. Patent No. 2,938,976, Wilson, assigned to the same assignee as the present invention, discloses a pressure actuated switch or circuit interrupter including a piston slida'ble in a connector body having terminals for breaking or closing circuits in cooperation with connector terminals joined to the connector body. The slidable piston is substantially instantaneously movable from an initial unactuated position to a final actuated position upon the introduction of fluid pressure into the device by pneumatic, hydraulic or explosive means.

In the arrangement described in the patent, the switch or interrupter is moved by the fluid pressure from an initial position to a final position, however, manual means must be employed to return the interrupting device to its original condition. It is one of the objects of the present invention to provide an improved circuit interrupter of this nature wherein the switching device can be reset by fluid pressure.

The arrangement described in the patent includes detent means consisting of O-rings and mating grooves for maintaining the movable interrupter piston in its two positions. These same O-rings perform the sealing function for the pressure chamber. It is another object of this invention to provide a circuit interrupter of this type having an improved mechanical releasable locking means for holding the interrupter piston in its two positions which can withstand a high shearing force. Another object of the invention is to provide such a locking means which is automatically operated by fluid pressure when the interrupter is triggered.

The electrical connector and circuit interrupter of the invention includes a cylindrical connector shell having a first portion of one diameter and a second portion of smaller diameter, and a piston slidably mounted in the connector shell. The piston is also formed of two different diameters and arranged so that together the piston and shell define an annular chamber which serves as a pressure chamber when sealing means are introduced between the piston and the shell at each end of the chamber. The electrical circuits to be interrupted are provided by termi'nals which are positioned in the piston and in insulator means mounted in the ends of the shell. The piston is axially movable from a first position to a second position upon the application of pressurized fluid through a port in the side wall of the cylindrical shell. By sealing the ends of the cylindrical shell and the spaces surrounding the terminals extending through the ends of the shell and by permitting fluid flow axially through the piston, pressure may be applied to an end face of the piston to reset the piston to its initial position without disassembly of the device.

As another feature of the invention, mechanical detents are provided in the side wall of the cylindrical shell which engage mating grooves within the piston to hold the piston in its two positions. The detents are pressure operated and by connecting one of the detents to the annular chamber and the other detent to the end chambers, the same pressure utilized to move the interrupter piston may be used to first release the detent locking means.

Further features, objects and attendant advantages will become apparent with reference to the following description and drawings in which:

FIG. 1 illustrates a side elevational view of two connector assemblies joined by a circuit inter-rupter incorporating the structure of the invention;

FIGS. 2 and 4 show end cross-sectional views of the interrupter;

FIG. 3 shows a side elevational cross-sectional view of the interrupter on line 3-3 of FIG. 2; and

FIG. 5 is a side elevational cross-sectional view of the interrupter on line 55 of FIG. 4 except that the interrupter is in the interrupted position.

In FIG. 1, a pair of electrical connector assemblies 10 and 12 are shown joined by a combined connector assembly and circuit interrupter 14. As explained, the interrupter assembly 14 is utilized to both connect and disconnect the various terminal circuit connections extending between the two connector assemblies.

Referring now to the other drawings also, the arrangement may be seen to include a generally cylindrical shell 16 having one end connected by suitable fasteners 18 to connector assembly 10 and the opposite end of the shell connected by a threaded member 20 to the connector assembly 12. Suitable gaskets 22 and 24 are provided to seal each end of the cylindrical shell to the connector assemblies 10 and 12. Each of the connector assemblies is provided with insulating members 26, 27 and 28 supporting a plurality of electric terminals, with one terminal 30 being illustrated in assembly 10 and another terminal 32 being shown in assembly 12. The terminals 30 and 32 are in turn connected to additional conductor means in the circuits to be connected. Suitable sealing members 34 and 36 are provided at the axially inner face of each connector assembly to prevent fluid leakage through the insulator or terminal portions of the assemblies.

Within the cylindrical shell 16 there is slidably positioned a piston interrupter assembly 38 including a generally cylindrical piston body 40 supporting insulator discs 42 and 44. These discs are formed with 'a plurality of axially aligned apertures 46 having tubular female terminal members 48 secured therein. As seen in FIGS. 3 and 5, terminal 48 is axially aligned with terminals 30 and 32 of the mating connector assemblies.

Cylindrical shell 16 is formed with a portion 16a of one diameter and a portion 16b of a smaller diameter. Piston body 40 is formed with an outwardly extending flange section 40a having a' diameter which fits snugly within shell portion 16a and a generally cylindrical section 40b which fits snugly within cylindrical walls of shell portion 1611 together with the cylindrical walls of piston section 4% and the opposing axial faces 40c and 16c of piston section 40a and shell portion 16b to define an annular pressure chamber 52. The chamber is variable in capacity as the piston slides within the shell 16 and hence may be best seen in FIG. 5 where it is in its largest size. Piston section 40a is formed with an annular groove carrying an O-ring or gasket 54 which produces a pneumatic seal be tween the piston and the shell at one end of the pressure chamber 52. Similarly, a gasket 56 is shown positioned in an annular groove formed in the side wall of shell portion 16b to provide a pneumatic seal between the piston and the shell at the opposite end of chamber 52.

As best seen in FIGS. 2, 3 and 5 pressure chamber 52 is in open communication with a tangential compartment 60 in cylindrical shell 16 having ports at either end to be connected to a source of pressurized fluid. In the drawings, the ports are closed by a pair of plugs 62 and 64.

When the circuit interrupter is to be placed into operation, one or both of the plugs may be removed and replaced by connection to a source of pressurized fluid. For example, a squib assembly (not shown) carrying an explosive charge which generates a compressed gas may be inserted therein. The squib assembly may be actuated by an electrical triggering device. Since the exact source of pressurized fluid is not necessary for an understanding of this invention, no illustration of the device is given; however, if desired further reference may be made to the aforementioned Wilson patent for a description.

Upon the application of pressurized fluid to chamber 52, piston assembly 38 is adapted to be moved axially from the position shown in FIG. 3 wherein the circuit through terminals 30, 48 and 32 is uninterrupted to the interrupted position shown in FIG. 5. As can be seen, socket terminal 48 has been slid further onto terminal pin 30 while the other end of the socket pin 48 has been separated from terminal pin 22. It should be understood that any number of circuits may be positioned in a given connector and that the piston assembly 38 may be used to complete a circuit as well as interrupt a circuit and a given connector may have both types of operation simultaneously.

As piston assembly 38 moves to the left as viewed in FIG. 3, the gas or fluid in the chamber 65 must be displaced. Since the axial face of the connector assembly 10 is sealed, the gas cannot escape in this fashion and instead it is forced axially through the interior of piston assembly 38 into chamber 66 formed at the opposite end of piston assembly 38 wherein a corresponding pressure reduction occurs as the piston assembly moves to the left. Such gas flow is indicated by arrows in FIG. through axial passages 68. A certain amount of fluid will also travel through the piston assembly in and around the terminals 48. It should be understood that the passages 68 may be positioned anywhere within the piston assembly and the cross-sectional area of the passages may be varied to fit the parameters of the given assembly.

In accordance with one aspect of the invention, the interrupter piston assembly 38 may be reset from the interrupted position of FIG. 5 to the uninterruped position of FIG. 3 by applying fluid pressure through end chambers 64 and 66. For this purpose, there is provided a port 70 formed in the side wall of cylindrical shell 16 opening into pressure chamber 66. A plug 72 shown in port 70 may be removed and replaced by a pressurized fluid connection when the interrupter is to be reset. Pressurized fluid applied through port 70 passes into chamber 66, through passages 68 in the piston assembly 38 and into end chamber 64 causing the piston assembly to return to its uninterrupted position shown in FIG. 3. This action takes place by virtue of the fact that the axial face of piston section 40a which is subjected to the pressurized fluid is greater in area than the axial face of piston section 40b with the result that the greater force produced causes the piston assembly to move in the desired manner. Typically, the pressure previously existing in chamber 52 has been dissipated by the time that the interrupter is to be reset; however, if not, the pressure may be released from chamber 52 by removing the pressure source connected thereto.

In accordance with .a further feature of the invention, positive detent means are provided to retain the piston interrupter in either of its extreme positions until a positive pressurized force is applied. A pair of detent assemblies 74 and 76 shown in FIGS. 1, 2 and 3 are provided for locking the piston assembly in the uninterrupted position and a pair of detent assemblies 78 and 80, shown in FIGS. 1, 4 and 5 are provided to hold the piston assembly in the interrupted position. Since the detent assemblies are substantially the same, only assembly 74 will be described in detail, it being understood that the description applies to all.

As shown in FIG. 2 shell 16 is provided a boss 81 .with a generally cylindrical radially extending bore 82 having a piston 84 slidably mounted therein. The outer end of piston 84 is engaged by one end of a coil spring 86 which has its outer end in contact with a cap 88 threadably secured onto the outer portion of boss 81. The spring 86 as positioned by sockets formed in the cap and the piston urges piston 84 radially inwardly. A piston pin 90 formed integral with piston 84 extends radially inwardly from cylinder 82 into the interior of shell 16 to cooperate with an annular groove 92 formed on the outer surface of the main piston 40. A pair of radially extending passages 94 connect the inner face of detent piston 84 with pressurized chamber 52. An O-ring or gasket positioned in an annular groove formed on detent piston 84 prevents fluid leakage outwardly into chamber 98 between piston 84 and cap 88.

In operation, detent piston 84 is normally urged radially inwardly by spring 86 so that its pin 90 is locked in annular groove 92 as shown in FIG. 3. To unlock the detent piston, pressurized fluid applied to chamber 52 in operating the interrupter is ducted by passages 94 to the radially inner surface of piston 84, forcing the piston outwardly against the urging of spring 86 so that pin 90 is withdrawn from groove 92. This releases the interrupter piston 40 so that it is free to be axially moved in response to a further increase in pressure.

From the foregoing, it will be realized that spring 86 must be selected so that its force will be overcome before the inertial and frictional forces of piston assembly 38 are overcome by the pressurized fluid introduced to chamber 52. The speed of operation is such that the detent is unlocked and the main piston assembly 38 is moved to the interrupted position in virtually simultaneous action. For example, in a working embodiment of the invention employing an electrically operated squib as the pressure source the circuit is interrupted in 20 milliseconds after current is applied to the squib; the switch or the main piston assembly actually moves within 5 milliseconds after peak pressure is obtained. The squib may apply as much as 800 pounds per square inch for pressure with the assembly 38 axpected to move with about 350 psi. The detent piston is expected to move under about 100 psi. to insure that the detent will be unlocked before the main assembly moves.

When detent assemblies 74 and 76 are in their locked positions, the other two detent assemblies 78 and are naturally in unlocked condition. Their detent piston pins are inelfectively engaging the outer surface of piston section 401) as illustrated in FIG. 4. As the piston assembly 38 is moved to the interrupted condition of FIG. 5, detent piston pin of assembly 78 has been forced radially inwardly by spring 86 into cooperation with annular groove thereby locking piston assembly 38 in its interrupted position. Similarly, detent assembly 80 (shown in FIG. 4) is also in the locked position.

When the piston assembly 38 is to be returned to the uninterrupted position by pressure applied through port 70, the pressure flow as indicated by arrows in FIG. 4, first reacts against the detent pistons of assemblies 78 and 8G popping them radially into their unlocked position. As the pressure increases, the piston assembly 38 is returned to the uninterrupted position of FIG. 3. After the piston assembly is locked in the interrupted position of FIG. 5 and the pressure in chamber 52 is dissipated, the detent pistons in detent assemblies 74 and 76 ride ineifectively on the outer surface of piston section 40b. 7

From the foregoing, it will be seen that the circuit interrupter is positively locked in its two positions to prevent any inadvertent movement and that a considerable shearing force would be required to destroy the locking effect of the detents. While two detents have been shown for each of the two interrupter positions, it should naturally be understood that more or less detents may be employed to obtain the desired locking action.

Similarly, it should be understood that while only a single embodiment of the invention has been illustrated, further changes and modifications will readily come to mind in the light of this disclosure; hence, it is intended that all such changes and modifications that fall within the true scope of the invention be included in the appended claims.

I claim:

1. In a pressure actuated electrical circuit interrupter, a cylindrical connector shell having a first portion of one diameter and a second portion of smaller diameter;

means closing and hermetically sealing the ends of said shell;

a piston slidably mounted in said shell having a first section which slides snugly within said first shell portion and a second section which slides snugly within said second shell portion;

said piston and shell forming end chambers on each end of said piston and an annular chamber defined by the cylindrical side walls of said shell first portion and said piston second section and by the opposing axial annular surfaces of said shell second portion and said piston first portion;

seal means extending between the shell and the piston at each end of the annular chamber to seal hermetically said annular chamber;

air passage means extending through said piston interconnecting said end chambers;

means defining a port formed in said shell opening into said annular chamber for introducing fluid pressure into said annular chamber to move said piston from a first axial position to a second axial position;

means defining a port formed in said shell opening into one of said end chambers for moving said piston from said second position to said first position.

2. The invention of claim 1 including electric terminal means positioned in said end means and extending into said shell; and mating terminal means positioned in said piston aligned to mate with the terminals in said end means, said terminal means being connected to complete a circuit in one of said positions and being disconnected to interrupt the circuit in the other of said positions.

3. The invention of claim 2 including seal means surrounding said terminal means in said end means.

4. The invention of claim 2 wherein said piston terminal means are unsealed so that some fluid flow therethrough is permitted.

5. The invention of claim 1 including means defining air passages axially through said piston for permitting air flow between said end chambers.

6. The invention of claim 1 including first detent means for locking said piston in said first position and second detent means for locking said piston in said second position.

7. The invention of claim 6 wherein said detent means are normally in position to hold said piston in its two positions and are pressure operated into unlocked position.

8. The invention of claim 7 wherein one of said pressure operated detent means is open to said annular chamber and the other of said detent means is open to one of said end chambers.

9. The invention of claim 6 wherein said detent means comprises a first pair of diametrically spaced detents l0. In a pressure actuated electrical circuit interrupter, a cylindrical connector shell having a first portion of one diameter and a second portion of smaller diameter;

a piston slidably mounted in said shell having a first section which slides snugly within said first shell portion and a second section which slides snugly within said second shell portion;

an annular chamber defined by the cylindrical side walls of said shell first portion and said piston second section and by the opposing axial annular sunfaces of said shell second portion and said piston first portion; seal means extending between the shell and piston at each end of the annular chamber to seal hermetically said annular chamber;

electrical insulator and terminal means positioned in the ends of said shell; electrical insulator and terminal means positioned in said piston;

said piston being movable from a first position wherein said electrical terminals are in con-tact to complete a circuit into a second position wherein said elec trical terminal means are not in contact so that the circuit is interrupted;

a port formed in said shell opening into said annular chamber for introducing fluid pressure to move said piston from one of said positions to the other position; and

pressure operated detent means in communication with said chamber for locking said piston in one of said positions.

11. The invention of claim 10 wherein said detent means includes a spring loaded piston and pin arrangement which normally locks said interrupter piston in a fixed axial position, but is movable into the unlocked position by pressure introduced to said chamber which forces the piston and pin into the unlocked position, said detent means being operable by pressure lower than that required to operate the interrupter piston.

12. The invention of claim 10 wherein said detent means comprises a radially extending bore formed in the side wall of said cylindrical shell, a cap closing the outer end of said bore to form a closed end detent cylinder opening into the interior of said shell, a detent piston slidably mounted within said detent cylinder to be movable radially within said detent cylinder with respect to said connector shell, a pin attached to said detent piston and extending radially inward into the axial path of said interrupter piston, means defining a circumferentially extending groove formed in said interrupter piston to receive said pin when the pin and the groove are aligned, a spring extending between said cap and said detent piston urging said detent piston and said pin radially inwardly so that the pin will snap into said groove when the interrupter piston is positioned with the groove aligned with the pin, and means defining passages interconnecting said detent cylinder and one of said pressure chambers so that upon application of pressure to said one chamber said detent cylinder and pin may be moved radially outwardly against the inward urging of said spring to release said pin from said groove thereby freeing said interrupter piston to be moved axially.

13. The invention of claim 12 wherein the charactertistics of said detent means are such that upon application of pressure to said one chamber said detent means will move into the unlocked position before the pressure is such that interrupter piston may be axially moved.

References Cited UNITED STATES PATENTS 2,938,976 5/1960 Wilson 200--82 BERNARD A. GILHEANY, Primary Examiner.

H. BROOME. Assistant Examiner. 

10. IN A PRESSURE ACTUATED ELECTRICAL CIRCUIT INTERRUPTER, A CYLINDRICAL CONNECTOR SHELL HAVING A FIRST PORTION OF ONE DIAMETER AND A SECOND PORTION OF SMALLER DIAMETER; A PISTON SLIDABLY MOUNTED IN SAID SHELL HAVING A FIRST SECTION WHICH SLIDES SNUGLY WITHIN SAID FIRST SHELL PORTION AND A SECOND SECTION WHICH SLIDES SNUGLY WITHIN SAID SECOND SHELL PORTION; AN ANNULAR CHAMBER DEFINED BY THE CYLINDRICAL SIDE WALLS OF SAID SHELL FIRST PORTION AND SAID PISTON SECOND SECTION AND BY THE OPPOSING AXIAL ANNULAR SURFACES OF SAID SHELL SECOND PORTION AND SAID PISTON FIRST PORTION; SEAL MEANS EXTENDING BETWEEN THE SHELL AND PISTON AT EACH END OF THE ANNULAR CHAMBER TO SEAL HERMETICALLY SAID ANNULAR CHAMBER; ELECTRICAL INSULATOR AND TERMINAL MEANS POSITIONE D IN THE ENDS OF SAID SHELL: ELECTRICAL INSULATOR AND TERMINAL MEANS POSITIONED IN SAID PISTON; SAID PISTON BEING MOVABLE FROM A FIRST POSITION WHEREIN SAID ELECTRICAL TERMINALS ARE IN CONTACT TO COMPLETE A CIRCUIT INTO A SECOND POSITION WHEREIN SAID ELECTRICAL TERMINAL MEANS ARE NOT IN CONTACT SO THAT THE CIRCUIT IS INTERRUPTED; A PORT FORMED IN SAID SHELL OPENING INTO SAID ANNULAR CHAMBER FOR INTRODUCTING FLUID PRESSURE TO MOVE SAID PISTON FROM ONE OF SAID POSITIONS TO THE OTHER POSITION; AND PRESSURE OPERATED DETENT MEANS IN COMMUNICATION WITH SAID CHAMBER FOR LOCKING SAID PISTON IN ONE OF SAID POSITIONS. 